(a) Field of the Invention
The invention relates to a method for separating a substrate and a thin-film material of an optical recording memory media using ultrasonic, and more particularly, to a method that places an optical recording memory media in an ultrasonic environment and uses ultrasonic to damage weaker interconnected interfaces of the optical recording memory media, thereby enabling the interconnected interfaces to absorb energies for attenuating or losing adhesive forces thereof with other layers.
(b) Description of the Prior Art
Compact discs are categorized according to physical properties thereof, and are generally distinguished as compact disc read-only-memory (CD-ROM), compact disc write-once (CD-WO) and compact disc re-writable (CD-RW). Take the CD-ROM for example, prior compact discs are a type of CD-ROM, and are formed by coating a reflective layer and a protective layer in sequence onto a substrate layer thereof. As for the CD-WO, a commonly known product is compact disc recordable (CD-R), which includes a recording layer, a reflective layer and a protective layer in sequence on a substrate layer thereof. In addition, regarding to the CD-WR, it is consisted of a dielectric layer, a recording layer, a dielectric layer, a reflective layer and a protective layer in sequence on a substrate layer thereof.
All of the aforesaid existing compact disc products have a substrate layer and a thin-film layer that form a main body of the compact disc. Wherein, the substrate layer that composes a main physical structure of the compact disc, is made of materials through which laser beams for reconstructing or recording data can be permeated. These materials, for instance, are made of polycarbonate resin, acrylic acid resin, polyolefine resin, or epoxy.
However, along with considerable increases in demand of the aforesaid compact discs, disposal and processing of waste compact discs have become a serious problem. In addition, damaged compact discs during manufacturing, disqualified compact discs scrapped by inspection after manufacturing, outdated inventory compact discs, and even breaking down of pirate compact discs, have further worsened disposal issues of compact discs.
With respect to disposal of compact discs, so far processes for the scrapped optical recording memory media s include crushing up and landfill, and burning. For the former process, locations for landfill are rather difficult to find, and especially metals contained in thin-film layers of optical recording memory media s yet cause concerns of re-contamination when being buried. For the latter process, special incinerators are needed. Nevertheless, exhaust gases produced from burning yet ought to be properly handled before emission thereof, and hence processing expenses and speeds are quite unsatisfactory. From recycling point of view, both of the aforesaid methods are unfavorable for subsequent recycling processes. For example, suppose a substrate layer in a scrapped optical recording memory media is a printed circuit, an expectation of having the compact disc recycled for serving as a substrate of other optical recording memory media s cannot be possibly reached. Or, even if waste compact discs are recycled to serve as engineering plastics having lower economical values instead of putting optical properties thereof to use, the aforesaid methods are still hardly accounted as appropriate.
To solve the aforesaid issues, there are reformations suggested by domestic and international patent publications or related information for overcoming the difficulties. Referring to the U.S. Pat. No. 5,306,349 and U.S. Pat. No. 6,600,229, scrapped optical recording memory media s are pre-processed using chemical solvents, and substrates and thin-films thereof are then agitated and separated using ultrasonic. Furthermore, referring to the U.S. Pat. No. 5,619,898, and the Taiwan Patent Publication No. 464595, Method and Device for Disposing Scrapped Compact Disc, external mechanical forces are utilized for removing the covered thin-film layer. Referring to the Taiwan Patent Publication No. 443949, Recycling Method for Compact Disc Writable, the compact disc is crushed into fragments and various materials therein are separated using solvents for further utilization. However, of the aforesaid methods, those that use chemicals are liable to cause problems of subsequent recycling and disposal of waste liquids, whereas those that use mechanical methods are unlikely to be completely recycled for compact disc substrates because the substrates are easily scratched. Above all, related equipments and methods of the aforesaid prior inventions are rather expensive and bulky as well as having tricky operations, and thus leading to inconveniences, time waste and complexities.
Furthermore, other methods that recycle the substrate material by removing the thin-film layer using chemical solutes are also proposed; for example, the Japan Patent No. 2615277, and the Japan Patent Publication No. 8-164524. According to the processing method recorded in the publications, the substrate materials are prone to physical changes during the processing thereof, and expected quality of recycled substrates may not be ensured. More particularly, an object of anticipating recycling an entire compact disc for serving as a substrate of other compact discs is basically improbable to achieve, and the recycled product is generally used as engineering plastics having lower economical values instead of being applied according to optical properties thereof. In addition, materials of the polycarbonate substrate after being processed by chemical solutes are likely affected. Not only the polycarbonate substrate cannot be implemented to optical applications having high values, but also mechanical properties thereof are affected, and hence again lowering utilization importance thereof. Besides, processing of the chemical solute wastes still remains as another problem that is not effortlessly solved.
In the view of the shortcomings of the aforesaid prior process methods of waste compact discs namely having high production cost and troublesome processing, being uneconomical and inefficiently recycled as well as hardly conforming to environmental-friendly requirements, the primary object of the invention is to provide a method for separating a substrate and a thin-film material of an optical recording memory media using ultrasonic. Wherein, a selectivity property of ultrasonic is employed for concentrating energies at interconnected interfaces between layers of a compact disc, and especially interconnected interfaces adjacent to a recording layer of the optical recording memory media. Through comparatively lower strengths of the interconnected interfaces, energies of ultrasonic are absorbed for parting and breaking away from other layers of the compact disc, thereby effectively and rapidly separating the substrate layer from the thin-film layer of the optical recording memory media. Original properties of the separated substrate layer and the thin-film layer are maintained for high-valued recycled products. Using the method according to the invention, highly efficient separation is accomplished by simple operations and lower production cost for subsequent recycling and re-uses. Therefore, the invention has excellences including being reliable, having low production cost and high-valued recycling.